Method and apparatus for identifying gaps between parts

ABSTRACT

A method, apparatus, and computer program product for identifying gaps. A grid of points is generated on a first surface. The grid of points is associated with a point for a first part associated with a second part in a model. A line segment is formed from the first surface of the first part to a second surface of the second part for each point in the grid of points to form a plurality of line segments. A gap size is identified between the first surface and the second surface using the plurality of line segments to form a plurality of gap measurements.

CROSS REFERENCE TO RELATED APPLICATION

The present invention is related to the following patent applicationentitled “Method and Apparatus for Deriving Associations between Partsand Fasteners”, Ser. No. ______, attorney docket no. 08-0826; filed evendate hereof, assigned to the same assignee, and incorporated herein byreference.

BACKGROUND INFORMATION

1. Field

The present disclosure relates generally to an improved data processingsystem and, in particular, to a method and apparatus for processingdata. Still more particularly, the present disclosure relates to amethod, apparatus, and computer program product for identifying gapsbetween parts.

2. Background

Computer aided design involves the use of computers or other dataprocessing systems to aid in the design of an object. These dataprocessing systems may include two-dimensional vector based draftingprograms and three-dimensional solid and surface modeling programs.Computer aided design programs are commonly used in aerospacemanufacturing to design and produce various objects such as, forexample, aircraft, space vehicles, aircraft engines, tools, buildings,medical devices, fuel tanks, and other suitable objects.

These types of systems are typically used for detailed engineering ofthree-dimensional and/or two-dimensional models of objects. These modelsinclude information used to create drawings of the objects. Thesedrawings may be, for example, two-dimensional and/or three-dimensionaldrawings. The models also may contain information about parts in theobjects. The information may include, for example, dimensions,materials, processing notes, product identifications, and other suitableinformation.

Computer aided design programs allow designers or engineers to lay outand develop various models for objects on a display device. Theinformation in the models, however, is not well organized. Typically,information may be associated with the particular components or parts ina model. Relationships, however, between those parts and other parts aretypically not present.

Currently, when information about parts in a model is needed, a user isrequired to go through the model to identify the needed information. Insome cases, the needed information may not be present in the model. Theuser may then be required to create the desired information based on areview of the information present in the model.

Therefore, it would be advantageous to have a method, apparatus, andcomputer program product that overcomes the issues described above.

SUMMARY

In one advantageous embodiment, a method is present for identifyinggaps. A grid of points is generated on a first surface. The grid ofpoints is associated with a point for a first part associated with asecond part in a model. A line segment is formed from the first surfaceof the first part to a second surface of the second part for each pointin the grid of points to form a plurality of line segments. A gap sizeis identified between the first surface and the second surface using theplurality of line segments to form a plurality of gap measurements.

In another advantageous embodiment, a data processing system comprises abus, a communications unit, a storage device, a processor unit connectedto the bus, and program code. The processor unit executes the programcode to generate a grid of points on a first surface, wherein the gridof points is associated with a point for a first part associated with asecond part in a model. The processor unit executes the program code toform a line segment from the first surface of the first part to a secondsurface of the second part for each point in the grid of points to forma plurality of line segments. The processor unit executes the programcode to identify a gap size between the first surface and the secondsurface using the plurality of line segments to form a plurality of gapmeasurements.

In yet another advantageous embodiment, a computer program product ispresent for identifying gaps. The computer program product comprises acomputer recordable storage medium and program code stored on thecomputer recordable storage medium. Program code is present forgenerating a grid of points on a first surface, wherein the grid ofpoints is associated with a point for a first part associated with asecond part in a model. Program code is present for forming a linesegment from the first surface of the first part to a second surface ofthe second part for each point in the grid of points to form a pluralityof line segments. Program code is present for identifying a gap sizebetween the first surface and the second surface using the plurality ofline segments to form a plurality of gap measurements.

The features, functions, and advantages can be achieved independently invarious embodiments of the present disclosure or may be combined in yetother embodiments in which further details can be seen with reference tothe following description and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The novel features believed characteristic of the advantageousembodiments are set forth in the appended claims. The advantageousembodiments, however, as well as a preferred mode of use, furtherobjectives and advantages thereof, will best be understood by referenceto the following detailed description of an advantageous embodiment ofthe present disclosure when read in conjunction with the accompanyingdrawings, wherein:

FIG. 1 is a diagram illustrating an aircraft manufacturing and servicemethod in accordance with an advantageous embodiment;

FIG. 2 is a diagram of an aircraft in which an advantageous embodimentmay be implemented;

FIG. 3 is a diagram of a data processing system in accordance with anillustrative embodiment;

FIG. 4 is a diagram of a model analysis environment in accordance withan advantageous embodiment;

FIG. 5 is a diagram illustrating a display of a structure in a model inaccordance with an advantageous embodiment;

FIG. 6 is a diagram illustrating a structure in accordance with anadvantageous embodiment;

FIG. 7 is a diagram illustrating bounding boxes in accordance with anadvantageous embodiment;

FIG. 8 is a diagram illustrating associations in a model in accordancewith an advantageous embodiment;

FIG. 9 is a diagram of a display of a part in accordance with anadvantageous embodiment;

FIG. 10 is a diagram illustrating line segments extending betweensurfaces of two parts in accordance with an advantageous embodiment;

FIG. 11 is an illustration of a table of gap information in accordancewith an advantageous embodiment;

FIG. 12 is a flowchart of a process for identifying associations in amodel of a structure in accordance with an advantageous embodiment;

FIG. 13 is a flowchart of a process for deriving associations betweenfasteners and parts in accordance with an advantageous embodiment;

FIG. 14 is a flowchart of a process for identifying gaps in accordancewith an advantageous embodiment;

FIG. 15 is a flowchart of a process for identifying gap information inaccordance with an advantageous embodiment; and

FIG. 16 is a flowchart of a process for associating potential parts withfastener locations in accordance with an advantageous embodiment.

DETAILED DESCRIPTION

Referring more particularly to the drawings, embodiments of thedisclosure may be described in the context of aircraft manufacturing andservice method 100 as shown in FIG. 1 and aircraft 200 as shown in FIG.2. Turning first to FIG. 1, a diagram illustrating an aircraftmanufacturing and service method is depicted in accordance with anadvantageous embodiment. During pre-production, aircraft manufacturingand service method 100 may include specification and design 102 ofaircraft 200 in FIG. 2 and material procurement 104.

During production, component and subassembly manufacturing 106 andsystem integration 108 of aircraft 200 in FIG. 2 takes place.Thereafter, aircraft 200 in FIG. 2 may go through certification anddelivery 110 in order to be placed in service 112. While in service by acustomer, aircraft 200 in FIG. 2 is scheduled for routine maintenanceand service 114, which may include modification, reconfiguration,refurbishment, and other maintenance or service.

Each of the processes of aircraft manufacturing and service method 100may be performed or carried out by a system integrator, a third party,and/or an operator. In these examples, the operator may be a customer.For the purposes of this description, a system integrator may include,without limitation, any number of aircraft manufacturers andmajor-system subcontractors; a third party may include, withoutlimitation, any number of venders, subcontractors, and suppliers; and anoperator may be an airline, leasing company, military entity, serviceorganization, and so on.

With reference now to FIG. 2, a diagram of an aircraft is depicted inwhich an advantageous embodiment may be implemented. The differentadvantageous embodiments may be used in the design of aircraft 200and/or structures for aircraft 200. In this example, aircraft 200 isproduced by aircraft manufacturing and service method 100 in FIG. 1 andmay include airframe 202 with a plurality of systems 204 and interior206.

Examples of systems 204 include one or more of propulsion system 208,electrical system 210, hydraulic system 212, and environmental system214. Any number of other systems may be included. Although an aerospaceexample is shown, different advantageous embodiments may be applied toother industries, such as the automotive industry. Apparatus and methodsembodied herein may be employed during any one or more of the stages ofaircraft manufacturing and service method 100 in FIG. 1.

In one illustrative example, different advantageous embodiments may beused during specification and design 102 in FIG. 1 of aircraft 200. Inparticular, the different advantageous embodiments may be applied toidentifying fastener and gap data during specification and design 102 inFIG. 1. Further, some advantageous embodiments also may be appliedduring maintenance and service 114 in FIG. 1 to design replacement partsand/or configuration changes to aircraft 200.

Turning now to FIG. 3, a diagram of a data processing system is depictedin accordance with an illustrative embodiment. Data processing system300 is an example of a data processing system that may be used toanalyze models to identify fasteners and/or gaps between parts. In thisillustrative example, data processing system 300 includes communicationsfabric 302, which provides communications between processor unit 304,memory 306, persistent storage 308, communications unit 310,input/output (I/O) unit 312, and display 314.

Processor unit 304 serves to execute instructions for software that maybe loaded into memory 306. Processor unit 304 may be a set of one ormore processors or may be a multi-processor core, depending on theparticular implementation. Further, processor unit 304 may beimplemented using one or more heterogeneous processor systems in which amain processor is present with secondary processors on a single chip. Asanother illustrative example, processor unit 304 may be a symmetricmulti-processor system containing multiple processors of the same type.

Memory 306 and persistent storage 308 are examples of storage devices. Astorage device is any piece of hardware that is capable of storinginformation either on a temporary basis and/or a permanent basis. Memory306, in these examples, may be, for example, a random access memory orany other suitable volatile or non-volatile storage device.

Persistent storage 308 may take various forms depending on theparticular implementation. For example, persistent storage 308 maycontain one or more components or devices. For example, persistentstorage 308 may be a hard drive, a flash memory, a rewritable opticaldisk, a rewritable magnetic tape, or some combination of the above. Themedia used by persistent storage 308 also may be removable. For example,a removable hard drive may be used for persistent storage 308.

Communications unit 310, in these examples, provides for communicationswith other data processing systems or devices. In these examples,communications unit 310 is a network interface card. Communications unit310 may provide communications through the use of either or bothphysical and wireless communications links.

Input/output unit 312 allows for input and output of data with otherdevices that may be connected to data processing system 300. Forexample, input/output unit 312 may provide a connection for user inputthrough a keyboard and mouse. Further, input/output unit 312 may sendoutput to a printer. Display 314 provides a mechanism to displayinformation to a user.

Instructions for the operating system and applications or programs arelocated on persistent storage 308. These instructions may be loaded intomemory 306 for execution by processor unit 304. The processes of thedifferent embodiments may be performed by processor unit 304 usingcomputer implemented instructions, which may be located in a memory,such as memory 306. These instructions are referred to as program code,computer usable program code, or computer readable program code that maybe read and executed by a processor in processor unit 304. The programcode in the different embodiments may be embodied on different physicalor tangible computer readable media, such as memory 306 or persistentstorage 308.

Program code 316 is located in a functional form on computer readablemedia 318 that is selectively removable and may be loaded onto ortransferred to data processing system 300 for execution by processorunit 304. Program code 316 and computer readable media 318 form computerprogram product 320 in these examples. In one example, computer readablemedia 318 may be in a tangible form such as, for example, an optical ormagnetic disc that is inserted or placed into a drive or other devicethat is part of persistent storage 308 for transfer onto a storagedevice, such as a hard drive that is part of persistent storage 308.

In a tangible form, computer readable media 318 also may take the formof a persistent storage, such as a hard drive, a thumb drive, or a flashmemory that is connected to data processing system 300. The tangibleform of computer readable media 318 is also referred to as computerrecordable storage media. In some instances, computer readable media 318may not be removable.

Alternatively, program code 316 may be transferred to data processingsystem 300 from computer readable media 318 through a communicationslink to communications unit 310 and/or through a connection toinput/output unit 312. The communications link and/or the connection maybe physical or wireless in the illustrative examples. The computerreadable media also may take the form of non-tangible media, such ascommunications links or wireless transmissions containing the programcode.

In some illustrative embodiments, program code 316 may be downloadedover a network to persistent storage 308 from another device or dataprocessing system for use within data processing system 300. Forinstance, program code stored in a computer readable storage medium in aserver data processing system may be downloaded over a network from theserver to data processing system 300. The data processing systemproviding program code 316 may be a server computer, a client computer,or some other device capable of storing and transmitting program code316.

The different components illustrated for data processing system 300 arenot meant to provide architectural limitations to the manner in whichdifferent embodiments may be implemented. The different illustrativeembodiments may be implemented in a data processing system includingcomponents in addition to or in place of those illustrated for dataprocessing system 300. Other components shown in FIG. 3 can be variedfrom the illustrative examples shown.

The different embodiments may be implemented using any hardware deviceor system capable of executing program code. As one example, the dataprocessing system may include organic components integrated withinorganic components and/or may be comprised entirely of organiccomponents excluding a human being. For example, a storage device may becomprised of an organic semiconductor.

As another example, a storage device in data processing system 300 isany hardware apparatus that may store data. Memory 306, persistentstorage 308, and computer readable media 318 are examples of storagedevices in a tangible form.

In another example, a bus system may be used to implement communicationsfabric 302 and may be comprised of one or more buses, such as a systembus or an input/output bus. Of course, the bus system may be implementedusing any suitable type of architecture that provides for a transfer ofdata between different components or devices attached to the bus system.Additionally, a communications unit may include one or more devices usedto transmit and receive data, such as a modem or a network adapter.Further, a memory may be, for example, memory 306 or a cache such asthat found in an interface and memory controller hub that may be presentin communications fabric 302.

The different advantageous embodiments recognize that some informationthat may be desirable in designing objects may include information aboutfasteners and parts that may be attached to each other using fasteners.The different advantageous embodiments recognize that this type ofinformation may be useful for identifying appropriate fasteners forsecuring or attaching parts to each other.

For example, the different advantageous embodiments recognize thatparameters, such as a fastener length, a diameter, a grip length, andother suitable parameters may depend on the parts to be attached to eachother. The different advantageous embodiments also recognize thatidentification of locations for fasteners and the parts to be attachedto each other by those fasteners may be useful in verifying whatfasteners should be used.

As another example, the different advantageous embodiments recognizethat a list of fasteners may be useful when a specific manufacturingsequence involving specific parts are present. As yet another example,the different advantageous embodiments recognize that a list offasteners and associated parts may be useful when structural repairsinvolve specific parts. Identification of fasteners also may be usefulfor a retrofit or modification of an aircraft.

The different advantageous embodiments recognize that this informationabout fasteners may not be available in a model. For example, someadvantageous embodiments may not contain fasteners. Instead, thedifferent advantageous embodiments recognize that these models mayinclude pierce points. These pierce points may be locations wherefasteners should be placed. As a result, the different advantageousembodiments recognize that a user is unable to search for informationabout fasteners because fasteners are not yet present in the model.

Thus, the different advantageous embodiments provide a method,apparatus, and computer program product for identifying associations ina model of a structure. In the different advantageous embodiments, anumber of fastener locations in the model of the structure areidentified. A number, as used herein, when referring to items, means oneor more items. For example, a number of fastener locations is one ormore fastener locations.

A line segment is extended through each of the number of fastenerlocations to form a number of line segments. The line segment extends aselected distance outside of an associated fastener location in thenumber of fastener locations. A number of parts is then identifiedthrough which the line segment extends to form a number of identifiedparts for a fastener for each of the number of line segments.

In this manner, a list or collection of information identifyingfasteners and parts associated with the fasteners may be identified.Parts associated with a fastener in these examples may be parts that areto be attached to each other using a fastener.

Further, the different advantageous embodiments also recognize thatinformation about gaps between parts is also not currently availablewithin models. The different advantageous embodiments recognize thatknowing whether changes in gaps between parts are present may be usefulin determining whether to redesign the part.

The different advantageous embodiments recognize that typically, a gapmay be designed between parts to account for variability of a part. Thedesign gap for part variability may allow for another part to be placedbetween those parts. This part may be referred to as a shim. Thedifferent advantageous embodiments recognize that if the gap isconstant, the manufacturing and placement of shims may be less timeconsuming and less expensive.

The different advantageous embodiments recognize that tapered gaps mayrequire special shims and different clamp loads. The differentadvantageous embodiments also recognize that these types of gaps maytake more time and more expense as compared to shims for consistent gapsbetween parts.

With the different advantageous embodiments, an identification of thesetypes of gaps may be used to either change the gap to a consistent gapand/or eliminate the gap. This information also may be used to identifywhether special shims and/or processing may be needed for particularparts.

Thus, the different advantageous embodiments provide a method,apparatus, and computer usable program code for identifying gaps. A gridof points is generated on a first surface. The grid of points isassociated with a point for a first part associated with a second partin a model. A normal vector that is normal to the first surface isidentified for each point in the grid of the grid of points to form anumber of normal vectors normal to the first surface.

A line segment between the first surface of the first part and thesecond surface of the second part is formed for each of the grid ofpoints to form a plurality of line segments. Each line segment isaligned with an associated normal vector. A gap size may then beidentified between the first surface and the second surface using theplurality of line segments to form a plurality of gap measurements. Inthis manner, revising a model and/or other operations involving themanufacturing of an object from the model may be performed based on thegap measurements.

With reference now to FIG. 4, a diagram of a model analysis environmentis depicted in accordance with an advantageous embodiment. In thisillustrative example, model analysis environment 400 includes modelprocessing system 402, which contains fastener analysis process 404 andgap analysis process 406. Model processing system 402 may be, forexample, a data processing system such as, for example, data processingsystem 300 in FIG. 3.

Fastener analysis process 404 is used to identify locations forfasteners and identify parts that may be associated with fasteners. Gapanalysis process 406 is used to identify gaps between parts. In theseillustrative examples, fastener analysis process 404 and gap analysisprocess 406 use model 408 as an input.

Model 408 is an electronic file or data structure containing information410 about parts 412. Information 410 may include, for example, drawings414 and attributes 416. Drawings 414 may be two-dimensional and/orthree-dimensional drawings for parts 412. Attributes 416 may provideinformation about parts 412 with respect to drawings 414.

For example, drawings 414 may contain drawings of part 418 and part 420in parts 412. Further, attributes 416 may include information aboutparts 418 and 420. Attributes 416 may include, for example, anidentification of part 418 and part 420. Further, attributes 416 alsomay include other information such as, for example, dimensioninformation, materials, notes, and other suitable information about part418 and part 420.

In these illustrative examples, fastener analysis process 404 generatesfastener data 422. Fastener data 422 may include information aboutfasteners and parts associated with fasteners from model 408. Forexample, fastener data 422 may contain an identification of part 418 andpart 420 as being associated with a fastener. In these examples,fastener data 422 is used by gap analysis process 406 to generate gapdata 424. Gap data 424 includes identification of gaps between partssuch as, for example, part 418 and part 420.

In operation, fastener analysis process 404 identifies fastenerlocations 428 within model 408. Fastener locations 428 may be locationswhere holes should be present to attach parts to each other. Thesefastener locations may be identified using pierce points 426, which maybe in attributes 416. A pierce point, in these examples, is a point on asurface. In these examples, a pierce point is a point through which ahole may be started.

Fastener analysis process 404 extends a line segment through each of thefastener locations within fastener locations 428 to form line segments430. Fastener analysis process 404 identifies parts 432 through which aline segment within line segments 430 extends. In these examples, parts432 are either all of parts 412 or a subset of parts 412.

In the different advantageous embodiments, the comparison of linesegments to parts may be performed by selecting a line segment from linesegments 430 and comparing that line segment to every part within parts412.

In some advantageous embodiments, part bounding boxes 434 for parts 412are compared to line segment bounding boxes 436 for line segments 430.For example, an intersection of a line segment bounding box in linesegment bounding boxes 436 with a number of part bounding boxes 434 mayidentify a number of potential parts from parts 412 that may beexamined.

In this manner, other parts within parts 412 are not compared with aparticular line segment. This use of bounding boxes may reduce the timeneeded to identify fasteners and their associations with parts.

In the different advantageous embodiments, gap analysis process 406generates gap data 424 using fastener data 422 in these examples. Gapanalysis process 406 takes fastener data 422 and generates grids 438using an identification of parts associated with each other throughfasteners in fastener data 422. In these examples, grid of points 440 isan example of a grid within grids 438. Grid of points 440 may be a gridof points on surface 442 on part 418.

Grids 438 may be generated on surfaces of parts based on pierce pointsthat may be present in fastener data 422. If the particular pair ofparts does not have a pierce point, a pierce point for that collectionof parts may be extended through a vector normal for the pierce point toidentify a point for a grid. Of course, any point may be selected on asurface between two parts to generate grids, in these examples.

Gap analysis process 406 identifies normal vectors 444 for each gridwithin grids 438. Thereafter, gap analysis process 406 generates linesegments 446 for each grid of points within grids 438. Line segments 446extend from surface 442 on part 418 to an opposing surface, such assurface 448 on part 420. The lengths of line segments 446 from surface442 to surface 448 are used to generate gap sizes 450.

Gap sizes 450 may be used by gap analysis process 406 to generate gapdata 424. For example, gap data 424 may include gap sizes 450.Additionally, gap data 424 also may include an analysis of gap sizes450. This analysis may include, for example, whether certain gaps withingap sizes 450 exceed a tolerance level. Additionally, gap data 424 mayindicate whether a tapered gap is present. Also, gap data 424 mayidentify whether an intersection between parts, such as part 418 andpart 420, have occurred.

The direction of line segments 446 may be maintained with respect tonormal vectors 444. The direction of these line segments may be used todetermine whether an intersection has occurred between parts, such aspart 418 and part 420.

In this manner, fastener data 422 and gap data 424 may be used toperform various operations. For example, fastener data 422 may be usedto identify fasteners that may be needed to attach parts to each otherwhen constructing an object from model 408. Fastener data 422 also maybe used to create a list of fasteners needed, verify current fastenersbeing used, and other suitable operations. Further, fastener data 422also may be used to revise a design of parts, depending on fastenersrequired to attach the parts.

Gap data 424 may be used to determine whether parts may be redesignedbecause of unacceptable gap sizes, shapes, or other attributes. Further,gap data 424 may be used to design shims for placement into the gaps.

The illustration of model analysis environment 400 in FIG. 4 is notmeant to imply physical or architectural limitations to the manner inwhich different advantageous embodiments may be implemented. Othercomponents in addition to or in place of the ones illustrated may beused. Also, in some advantageous embodiments, fewer components may berequired.

In one example, fastener analysis process 404 and gap analysis process406 may be located on different data processing systems on a network.Further, model 408 may be located remotely or as part of modelprocessing system 402. Also, multiple models may be analyzed using thedifferent advantageous embodiments.

With reference now to FIG. 5, a diagram illustrating a display of astructure in a model is depicted in accordance with an advantageousembodiment. In this example, display 500 illustrates a perspective viewof structure 502. Structure 502 contains parts 504, 506, and 508. Part504 may be a skin panel, part 506 may be an intercostal, and part 508may be a rib.

The presentation of these parts in display 500 are examples of partssuch as, for example, parts 412 in model 408 in FIG. 4. In this example,pierce points 510 with line segments 512 are illustrated. Pierce point514 is an example of a pierce point within pierce points 510, and linesegment 516 is an example of a line segment within line segments 512.

Line segments 512 are aligned with vectors that are normal to surface518 of part 504. As can be seen in this example, pierce points 510originate on surface 518 of part 504. Line segments 512 are normal tosurface 518 in these examples. Although line segments 512 areillustrated as normal to surface 518, other advantageous embodiments mayalign line segments 512 with vectors that may not be normal to surface518.

With reference now to FIG. 6, a diagram illustrating a structure isdepicted in accordance with an advantageous embodiment. In display 600,structure 502 is shown in a lower perspective view. In this illustrativeexample, part 604 also can be seen for structure 502. Part 604 is asplice plate, in this depicted example.

Further, in this view of structure 502, pierce points 606 and 608 arepresent on part 506. Pierce point 606 has line segment 610, while piercepoint 608 has line segment 612 extending from surface 614 of part 506.Line segments 610 and 612 extend through part 506 and part 508 in theseexamples. As a result, these two line segments may be used to identifyfasteners that are to be associated with parts 506 and 508.

In this example, line segment 516 extends through both part 504 and part506. A comparison of line segment 516 with part 504, part 506, and part508 identifies parts 504 and 506 as parts through which line segment 516extends. This identification may be used to generate an association oridentification of fasteners for parts 504 and 506 at pierce point 514.

In the different advantageous embodiments, each line segment is comparedto every part within structure 502. This comparison is made to determinewhether the line segment extends through a particular part withinstructure 502.

The different advantageous embodiments recognize that this type ofcomparison may use additional processor time and/or other computingresources to generate an identification of fasteners for parts when alarge number of parts and fasteners are to be used in a structure.

In this depicted example, line segment 612 may be compared with parts504, 506, 508, and 604. This comparison identifies parts 506 and 508 asparts through which line segment 612 extends. A similar comparison ismade for every line segment in line segments 512 in FIG. 5, in theseexamples.

In other advantageous embodiments, other numbers of parts may be presentfor structure 502. For example, in some advantageous embodiments, 10parts, 25 parts, 100 parts, 1,000 parts, or some other suitable numberof parts may be present for structure 502. As the number of partsincreases, the comparison of a line segment with every part in thestructure may increase the time needed to identify parts for associationwith fasteners. The different advantageous embodiments may reduce theamount of time needed through the use of bounding boxes.

With reference now to FIG. 7, a diagram illustrating bounding boxes isdepicted in accordance with an advantageous embodiment. Bounding boxes700, 702, 704, and 706 are bounding boxes for parts 504, 506, 508, and604 in FIGS. 5 and 6, respectively. These bounding boxes are typicallygenerated for models of structures.

The different advantageous embodiments also generate bounding boxes forline segments. In this example, bounding box 708 is generated for linesegments 610 and 612. In this illustrative example, bounding box 708encompasses two line segments. Of course, bounding box 708 may begenerated to encompass other numbers of line segments such as, forexample, one line segment, three line segments, 10 line segments, orsome other suitable number of line segments.

The intersection of bounding box 708 with bounding boxes 700, 702, and704 identifies the associated parts as potential parts through whichline segments 610 and 612 may be passed. These bounding boxes are madeto identify groupings of parts for comparison to a number of linesegments. In these illustrative examples, these bounding boxescorrespond to parts 504, 506, 508, and 604 in FIGS. 5 and 6,respectively.

A comparison of these line segments using these bounding boxes is madeto identify potential parts for analysis rather than comparing theseline segments to every part in structure 502 in FIG. 5. Although onlyone less comparison is made in these examples, in other advantageousembodiments, when additional numbers of parts are present, the number ofcomparisons may be reduced by even larger numbers.

With reference now to FIG. 8, a diagram illustrating associations in amodel is depicted in accordance with an advantageous embodiment. Table800 is an example of fastener data 422 in FIG. 4. Table 800 is anexample of fastener identifications and part associations that may begenerated from structure 502 in FIG. 5. In this example, table 800illustrates associations between fasteners and parts.

Table 800 includes identification of fasteners in column 802. Parts maybe identified in columns 804, 806, and 808. An identification ofsurfaces for the parts is located in column 810. The identification ofsurfaces in column 810 is a location on a surface where a line segmentintersected the surface of the part. The information in table 800 may beused to identify and analyze gaps in structure 502 in FIG. 5, in theseexamples.

With reference now to FIG. 9, a diagram of a display of a part isdepicted in accordance with an advantageous embodiment. In this example,display 900 is a top view of structure 902. Structure 902 contains parts904, 906, and 908.

Pierce points 910, 912, 914, and 916 are present on surface 918 of part906. Grids of points 920, 922, 924, and 926 are formed relative topierce points 910, 912, 914, and 916, respectively.

In this example, grids of points 920, 922, 924, and 926 are constructedaround pierce points 910, 912, 914, and 916. In these examples, thepoints in a grid of points may be symmetrically spaced around a piercepoint. The spacing of points around pierce points 910, 912, 914, and 916may be spaced in a number of different ways.

In these examples, a grid of points is selected to have an area that issquare in shape and four times the fastener diameter on each side. Ofcourse, other types of selections may be made. For example, if fastenershave not yet been added to the model, a quarter inch spacing on a fourby four grid may be used.

In this illustrative example, line segments 928 extend from surface 918located on pierce point 910. Line segments 930 extend from surface 918located on pierce point 912. Line segments 932 extend from surface 918located on pierce point 914. Line segments 934 extend from surface 918located on pierce point 916. These line segments extend in a directionthat is normal to surface 918 towards part 904, which is shown inphantom in this example, to illustrate the extension of line segments.

With reference now to FIG. 10, a diagram illustrating line segmentsextending between surfaces of two parts is depicted in accordance withan advantageous embodiment. In this example, display 1000 provides aside view of parts 904 and 906.

In this depicted example, line segments 928, 930, 932, and 934 extendfrom surface 918 of part 906 to surface 1002 of part 904. As can be seenin this depicted example, some line segments, such as line segment 1004,extend from surface 918 to surface 1002 in a direction that is oppositefrom line segment 1006.

This change in direction may be identified using direction vectors orpositive and negative values to identify intersections between partssuch as, for example, part 904 and part 906. In this example, segment1004 may have a negative value to indicate an intersection, whilesegment 1006 may have a positive value.

As can be seen, surface normals are generated for each point, and thenormals are used to find intersecting points on opposing surfaces for anopposing part. The length of the segments may be used to identify gapsthat may be present.

With reference now to FIG. 11, an illustration of a table of gapinformation is depicted in accordance with an advantageous embodiment.Table 1100 is an example of one form for gap data 424 in FIG. 4.

In this example, table 1100 contains locations in column 1102, and gapinformation in columns 1104 and 1106. In these examples, an entry of NIin column 1104 indicates that no intersection has occurred. The valuesin column 1104 also take into account the direction which may beidentified by positive and negative values. The values in column 1106are magnitudes and do not contain directional information.

Additionally, table 1100 includes range information in row 1108. Medianvalues are shown in row 1110 in this example. Of course, in otheradvantageous embodiments, other types of information may be included,depending on the particular implementation. For example, anidentification of a location with gaps that exceed a range limit may beidentified.

Further, in addition to using a table such as, for example, table 1100,the gap data may take other forms. For example, a display may illustratethe pierce points with colors for different gap lengths. Alternatively,the gap lengths may be identified using a contoured map or some othersuitable form of presentation.

With reference now to FIG. 12, a flowchart of a process for identifyingassociations in a model of a structure is depicted in accordance with anadvantageous embodiment. The process illustrated in FIG. 12 may beimplemented in a software component such as, for example, fasteneranalysis process 404 in FIG. 4.

The process begins by identifying a number of fastener locations in themodel of the structure (operation 1200). In these examples, the fastenerlocations may be identified through pierce points and/or holes that maybe present in the model of a structure.

A line segment is extended through each of the number of fastenerlocations to form a number of line segments (operation 1202). Each linesegment extends a selected distance outside of an associated fastenerlocation in the number of fastener locations. The selected distance mayvary.

For example, the line segment may extend in a direction normal to thesurface on which a fastener location is present. The line segment mayextend in each direction from the surface for a distance that may bebased on the fastener.

The process then identifies a number of parts through which the linesegment extends to form a number of identified parts for a fastener foreach of the number of line segments (operation 1204). The process maythen sort part information for the number of identified parts based on adistance from which the line segment intersects a surface of a part inthe number of parts (operation 1206), with the process terminatingthereafter. In operation 1206, each part may be identified based on itslocation relative to when the part is pierced or intersected by the linesegment extending from the surface of the fastener location.

Of course, in some advantageous embodiments, if the line segment onlyextends or pierces one surface of a part, the line segment may beextended in length to pierce or extend through the other surface of thepart. The line segment may also be reduced in length to not extendthrough the part at all.

With reference now to FIG. 13, a flowchart of a process for derivingassociations between fasteners and parts is depicted in accordance withan advantageous embodiment. The process illustrated in FIG. 13 is anexample of a process that may be implemented in a software componentsuch as, for example, fastener analysis process 404 in FIG. 4.

The process begins by generating a bounding box for each fastener in anumber of fasteners (operation 1300). Thereafter, bounding boxes areobtained for the parts in the structure (operation 1302). The processthen identifies a number of parts that have bounding boxes that overlapa bounding box for a fastener for each of the number of fasteners(operation 1304).

The process then identifies fastener vectors (operation 1306). In theseexamples, the fastener vectors are vectors that are normal to thesurface of the part on which a fastener location is present. Thefastener vectors may, in some cases, not be normal to the outer surface.

The process generates a line segment based on the identified fastenervectors for each of the fastener locations to form a plurality of linesegments (operation 1308). The process then selects a group of parts fora number of fasteners for processing (operation 1310). The process thenselects a fastener from the number of fasteners (operation 1312). Insome advantageous embodiments, a bounding box may contain more than onefastener.

The process then identifies each part within the group through which theline segment extends (operation 1314). In some advantageous embodiments,a line segment may be considered to extend through a part only if theline segment extends through both surfaces of a part. If only onesurface of a part is intersected by the line segment, this line segmentmay be saved for later processing. A determination is made as to whetherany line segments are present in which only one surface of the part hasbeen intersected (operation 1316).

If line segments are present in which only one surface has beenintersected, the process adjusts the line segment length for these linesegments (operation 1318). This operation may identify line segmentsthat may have only intersected a portion of a part. The line segmentlength may be adjusted to determine whether a different fastener may beneeded, if a redesign may occur, and/or some other suitable action maybe taken. The process then returns to operation 1314, as describedabove.

With reference again to operation 1316, if line segments are not presentin which only one surface has been intersected, the process sorts thepoints, surfaces, and parts by distance from a pierce point (operation1320). The process then stores the data as fastener data (operation1322).

The process determines whether additional fasteners are present in thegroup (operation 1324). If additional fasteners are present, the processreturns to operation 1312. Otherwise, a determination is made as towhether additional groups are present for processing (operation 1326).If additional groups are present for processing, the process returns tooperation 1310. If no additional groups are present for processing, theprocess terminates.

With reference now to FIG. 14, a flowchart of a process for identifyinggaps is depicted in accordance with an advantageous embodiment. Theprocess illustrated in FIG. 14 may be implemented in a softwarecomponent such as, for example, gap analysis process 406 in FIG. 4.

The process begins by generating a grid of points in a first surface(operation 1400). The grid of points is associated with a point for afirst part associated with a second part in a model.

The process then forms a line segment from the first surface of thefirst part to a second surface of the second part for each of the gridpoints to form a plurality of line segments (operation 1402). Each linesegment in the plurality of line segments is aligned with an associatednormal vector for the surface. The process then identifies a gap sizebetween the first surface and the second surface using the plurality ofline segments to form a plurality of gap measurements (operation 1404),with the process terminating thereafter.

With reference now to FIG. 15, a flowchart of a process for identifyinggap information is depicted in accordance with an advantageousembodiment. The process illustrated in FIG. 15 may be implemented in asoftware process such as, for example, gap analysis process 406 togenerate gap data 424 in FIG. 4.

The process begins by selecting a surface pair for a fastener location(operation 1500). The process then intersects a fastener directionvector and one surface (operation 1502). In operation 1502, the fastenerdirection vector is a vector that may extend in a direction normal to asurface at the location of a pierce point.

In some advantageous embodiments, the vector may extend in a directionthat is not normal to the surface at the location of the pierce point.If the pierce point is on a surface other than the surfaces of interestbetween two parts, the fastener direction vector may be used to identifythe point on the surface of interest. If the pierce point is located onthe surface of interest, this operation may be omitted.

A grid of points is generated using the intersection (operation 1504).The process then finds a surface normal at each grid point in the gridof points (operation 1506).

Next, the process generates a line segment along each surface normalthat is bounded by the surface of the first part and the surface of thesecond part (operation 1508). In other words, the line segment extendsfrom one surface to another surface. The process then identifies thelength of the line segment (operation 1510). This length may be negativeif the parts intersect each other. A determination is then made as towhether additional unprocessed fastener locations for surface pairs arepresent (operation 1512). If additional fastener locations are present,the process returns to operation 1500.

Otherwise, a determination is made as to whether negative values arepresent in the length (operation 1514). If negative values are present,a flag is set (operation 1516). Otherwise, the process identifies arange of lengths in the set (operation 1518). The process also proceedsto operation 1518 from operation 1516. The range of lengths may beperformed for a single grid if multiple fasteners are present that maybe located within a grid.

In other words, if two fasteners have overlapping grids, operation 1518may be performed only for a single grid or for both grids, depending onthe particular implementation. The process then sets a flag if the rangeexceeds a threshold (operation 1520), with the process terminatingthereafter.

With reference now to FIG. 16, a flowchart of a process for associatingpotential parts with fastener locations is depicted in accordance withan advantageous embodiment. The process illustrated in FIG. 16 may beimplemented in a software component, such as fastener analysis process404 in FIG. 4.

The process begins by identifying a bounding box for the fastener foreach of a number of fastener locations to form a first number ofbounding boxes (operation 1600). The bounding boxes may have a shapebased on a fastener that may be used at the fastener location. Abounding box may be identified for each of the number of parts to form asecond number of bounding boxes (operation 1602).

A number of intersections between the first number of bounding boxes andthe second number of bounding boxes is identified to form a number ofintersections (operation 1604). A number of parts may then be associatedwith each fastener in the number of fasteners in which an intersectionoccurred to form a number of potential parts for each fastener in thenumber of fasteners (operation 1606), with the process terminatingthereafter. In this manner, a smaller number of parts may be comparedwith line segments for a fastener location based on intersections ofbounding boxes for the parts with a bounding box for a fastenerlocation.

The flowcharts and block diagrams in the different depicted embodimentsillustrate the architecture, functionality, and operation of somepossible implementations of apparatus, methods and computer programproducts. In this regard, each block in the flowchart or block diagramsmay represent a module, segment, or portion of computer usable orreadable program code, which comprises one or more executableinstructions for implementing the specified function or functions.

In some alternative implementations, the function or functions noted inthe blocks may occur out of the order noted in the figures. For example,in some cases, two blocks shown in succession may be executedsubstantially concurrently, or the blocks may sometimes be executed inthe reverse order, depending upon the functionality involved.

Thus, the different advantageous embodiments provide a method,apparatus, and computer program code for identifying associations andgap data. These associations are parts that are associated withfasteners or locations for fasteners in these examples.

The associations may be identified by identifying a number of fastenerlocations in the model of the structure. A line segment may be extendedthrough each of the fastener locations to form a number of line segmentsin which the line segment extends a selected distance away from theassociated fastener location in the number of fastener locations. Anumber of parts is identified through which the line segment extends toform a number of identified parts for a fastener for each of the numberof line segments.

The gap data may be identified by generating a grid of points on a firstsurface in which the grid of points is associated with a point for afirst part associated with a second part in a model. A line segment isformed from the first surface of the first part to the second surface ofthe second part for each of the grid parts to form a plurality of linesegments in which each line segment in the plurality of line segments isaligned with an associated normal vector. A gap size is identifiedbetween the first surface and the second surface using the plurality ofline segments to form a plurality of gap measurements.

With this information, changes to designs, selection of fasteners,designs for shims, generation of instructions to assemble parts, andother suitable operations may be performed. Using the differentadvantageous embodiments, the identification of the information may beperformed with less time and effort. In some cases, the identificationof the information may be too time consuming to perform depending on thecomplexity of the structure.

The different advantageous embodiments can take the form of an entirelyhardware embodiment, an entirely software embodiment, or an embodimentcontaining both hardware and software elements. Some embodiments areimplemented in software, which includes, but is not limited to, formssuch as, for example, firmware, resident software, and microcode.

Furthermore, the different embodiments can take the form of a computerprogram product accessible from a computer usable or computer readablemedium providing program code for use by or in connection with acomputer or any device or system that executes instructions. For thepurposes of this disclosure, a computer usable or computer readablemedium can generally be any tangible apparatus that can contain, store,communicate, propagate, or transport the program for use by or inconnection with the instruction execution system, apparatus, or device.

The computer usable or computer readable medium can be, for example,without limitation, an electronic, magnetic, optical, electromagnetic,infrared, or semiconductor system, or a propagation medium. Non-limitingexamples of a computer readable medium include a semiconductor or solidstate memory, magnetic tape, a removable computer diskette, a randomaccess memory (RAM), a read-only memory (ROM), a rigid magnetic disk,and an optical disk. Optical disks may include compact disk-read onlymemory (CD-ROM), compact disk-read/write (CD-R/W), and DVD.

Further, a computer usable or computer readable medium may contain orstore a computer readable or usable program code such that when thecomputer readable or usable program code is executed on a computer, theexecution of this computer readable or usable program code causes thecomputer to transmit another computer readable or usable program codeover a communications link. This communications link may use a mediumthat is, for example, without limitation, physical or wireless.

A data processing system suitable for storing and/or executing computerreadable or computer usable program code will include one or moreprocessors coupled directly or indirectly to memory elements through acommunications fabric, such as a system bus. The memory elements mayinclude local memory employed during actual execution of the programcode, bulk storage, and cache memories which provide temporary storageof at least some computer readable or computer usable program code toreduce the number of times code may be retrieved from bulk storageduring execution of the code.

Input/output or I/O devices can be coupled to the system either directlyor through intervening I/O controllers. These devices may include, forexample, without limitation, keyboards, touch screen displays, andpointing devices. Different communications adapters may also be coupledto the system to enable the data processing system to become coupled toother data processing systems or remote printers or storage devicesthrough intervening private or public networks. Non-limiting examplesare modems and network adapters and are just a few of the currentlyavailable types of communications adapters.

The description of the different advantageous embodiments has beenpresented for purposes of illustration and description, and it is notintended to be exhaustive or limited to the embodiments in the formdisclosed. Many modifications and variations will be apparent to thoseof ordinary skill in the art. Further, different advantageousembodiments may provide different advantages as compared to otheradvantageous embodiments.

The embodiment or embodiments selected are chosen and described in orderto best explain the principles of the embodiments, the practicalapplication, and to enable others of ordinary skill in the art tounderstand the disclosure for various embodiments with variousmodifications as are suited to the particular use contemplated.

1. A method for identifying gaps, the method comprising: generating agrid of points on a first surface, wherein the grid of points isassociated with a point for a first part associated with a second partin a model; forming a line segment from the first surface of the firstpart to a second surface of the second part for each point in the gridof points to form a plurality of line segments; and identifying a gapsize between the first surface and the second surface using theplurality of line segments to form a plurality of gap measurements. 2.The method of claim 1 further comprising: analyzing the plurality of gapmeasurements to determine whether an unacceptable gap is present in theplurality of gap measurements.
 3. The method of claim 1 furthercomprising: determining whether a tapered gap is present from theplurality of gap measurements.
 4. The method of claim 1 furthercomprising: revising the model of the first part and the second partbased on the plurality of gap measurements.
 5. The method of claim 1further comprising: identifying a direction of each segment in theplurality of line segments formed from the first surface to the secondsurface to form a number of directions; and identifying a number of linesegments having an opposite direction to an associated normal vector. 6.The method of claim 5, wherein the opposite direction indicates anintersection between the first part and the second part.
 7. The methodof claim 1, wherein each of the plurality of line segments extend in adirection normal to the first surface for each associated point in thegrid of points.
 8. The method of claim 1, wherein the point on the firstsurface is a pierce point for a fastener.
 9. The method of claim 1,wherein the first part and the second part are part of an object,wherein the object is selected from one of a mobile platform, astationary platform, a land-based structure, an aquatic-based structure,a space-based structure, an aircraft, a surface ship, a tank, apersonnel carrier, a train, a spacecraft, a space station, a satellite,a submarine, an automobile, a power plant, a bridge, a dam, amanufacturing facility, an engine, a tool, a wing, a fuselage, a fueltank, and a building.
 10. A data processing system comprising: a bus; acommunications unit connected to the bus; a storage device connected tothe bus, wherein the storage device includes program code; and aprocessor unit connected to the bus, wherein the processor unit executesthe program code to generate a grid of points on a first surface,wherein the grid of points is associated with a point for a first partassociated with a second part in a model; form a line segment from thefirst surface of the first part to a second surface of the second partfor each point in the grid of points to form a plurality of linesegments; and identify a gap size between the first surface and thesecond surface using the plurality of line segments to form a pluralityof gap measurements.
 11. The data processing system of claim 10, whereinthe processor unit further executes the program code to revise the modelof the first part and the second part based on the plurality of gapmeasurements.
 12. The data processing system of claim 10, wherein theprocessor unit further executes the program code to determine whether atapered gap is present from the plurality of gap measurements.
 13. Thedata processing system of claim 10, wherein the processor unit furtherexecutes the program code to analyze the plurality of gap measurementsto determine whether an unacceptable gap is present in the plurality ofgap measurements.
 14. The data processing system of claim 10, whereinthe processor unit further executes the program code to identify adirection of each segment in the plurality of line segments formed fromthe first surface to the second surface to form a number of directions;and identify a number of line segments having an opposite direction toan associated normal vector.
 15. The data processing system of claim 14,wherein the opposite direction indicates an intersection between thefirst part and the second part.
 16. A computer program product foridentifying gaps, the computer program product comprising: a computerrecordable storage medium; program code, stored on the computerrecordable storage medium, for generating a grid of points on a firstsurface, wherein the grid of points is associated with a point for afirst part associated with a second part in a model; program code,stored on the computer recordable storage medium, for forming a linesegment from the first surface of the first part to a second surface ofthe second part for each point in the grid of points to form a pluralityof line segments; and program code, stored on the computer recordablestorage medium, for identifying a gap size between the first surface andthe second surface using the plurality of line segments to form aplurality of gap measurements.
 17. The computer program product of claim16 further comprising: program code, stored on the computer recordablestorage medium, for revising the model of the first part and the secondpart based on the plurality of gap measurements.
 18. The computerprogram product of claim 16 further comprising: program code, stored onthe computer recordable storage medium, for determining whether atapered gap is present from the plurality of gap measurements.
 19. Thecomputer program product of claim 16 further comprising: program code,stored on the computer recordable storage medium, for analyzing theplurality of gap measurements to determine whether an unacceptable gapis present in the plurality of gap measurements.
 20. The computerprogram product of claim 16 further comprising: program code, stored onthe computer recordable storage medium, for identifying a direction ofeach segment in the plurality of line segments formed from the firstsurface to the second surface to form a number of directions; andprogram code, stored on the computer recordable storage medium, foridentifying a number of line segments having an opposite direction to anassociated normal vector.